A gas lighter, gas candle, hair curler, iron, soldering gun, lamp, or the like can be provided with a gas supply constituted as a reservoir bottle that is filled with the combustible gas in liquid form. The reservoir can be a permanent part of the piece of equipment or can be disposable.
So long as it is in liquid condition, a normally gaseous combustible is a body comprises of a single component or blend of components that are liquid at the pressure and temperature at which it is normally stored, the liquid phase being in thermodynamic equilibrium with its gaseous phase. Once this equilibrium has been attained, the interface between the two phases is planar when they alone occupy the reservoir. This interface has a radius of curvature when the liquid phase is held in a porous body, for instance made of a block of felted fibers. In this case the viscosity and the surface tension of the liquid phase allow a modification of the liquid/vapor equilibrium and retention of the liquid phase in the middle of the porous body.
The gas can also be dissolved in a thickening or gelling solvent such as in particular polymers of low molecular weight such as methacrylates, fatty acids like sodium palmitate, colloidal silicates, carboxyl acid salts of aluminum, and the like.
The reservoir is normally provided with a valve for controlling the outflow of the combustible, typically with a pressure-reducing filter. This outflow controller is set up to work with the liquid or the gaseous phase as it is virtually impossible to design such a controller that can operate with both phases or with the phases mixed. Since the gaseous phase is always above the liquid phase, the reservoir is typically provided with an outlet on its upper wall and the outflow controller is set to work with the gaseous phase only.
When the reservoir is, as is typical, of cylindrical shaped with upper and lower walls perpendicular to the axis of the cylinder, the outlet is centrally formed in the top wall. A cylindrical porous block is used to hold a large quantity of the combustible. The problem with this standard construction is that when the reservoir is overfilled, as is possible in a fast mass-production operation, the excess liquid is not all trapped in the porous body so that the liquid itself can get into the outlet. This blocks it and makes the system nonoperational.